#define _CRT_SECURE_NO_WARNINGS 1

#include<stdio.h>
#include<string.h>

int main()
{
	char arr1[20] = "abcdefg";
	char arr2[] = "xxxxxxxxxxxxx";
	char* ret = strncat(arr1, arr2, 7);
	printf("%s\n", arr1);
	printf("%s\n", ret);
	return 0;
}